Throttle valve



Jimflly l 1924.

w. G. NAISMITH THROTTLE VALVE Filed March 18. 1921 INVENTOR.

ATTORNEY.

Patents July l, 1241-.

WILLIAM G. uvarsivirrn, or DENVER, COLORADO, ASSIGNOR To THE DENVER ROCK DRILL MANUFACTURING COMPANY, or DENVER, COLORADO, A CORPORATION OF DELAWARE.

\ THROTTLE VALVE.

Application filed March 18, 1921. Serial No. 453,237.

To all whom it may concern. 1

Be it known that 1, WILLIAM G. NAI- SMITH, a subject of the King ofGreat Britain, residing at Denver, in the county of Denver and State of Colorado, have invented certain new and useful Improvements in Throttle Valves, of which the following is a specification.

The present invention relates more particularly to throttle or controlling valves for rock drills, but may be employed for other purposes. As is well known it is the common practice to employ rotary valves having tapered bearing portions and to introduce the motive fluid to the valve casing so that it will operate against the major end of the valve'to produce end thrusts. The pressure of the fluid is thus in adirection to force the tapered portion into engagement with its seat, creating a wedging action. While this is essential, the pressure is often so great as to cause the valve to stick and be operated only with difficulty.

It has been proposed to relieve a portion of this pressure by isolating a part of the pressure surface and giving a vent from this surface to atmosphere, but it has been found that in some cases there is a tendency when the drill is in operation for the valve to close due partly to the reduced pressure combined with the vibration incident to the running'of the drill.

The object of the present invention is to overcome this tendency by providing means that will afford suflicient pressure to hold the valve and yet permit its easy actuation.

In the accompanying drawing Figure 1 is a longitudinal sectional view through a portion of a drilling machine, showing the improved Valve mechanism,

Figures 2 and 8 are cross sectional views substantially on the line 22 of Figure 1 and on an enlarged scale, respectively showing the valve in its opened and closed positions. i

Figure 4 is a perspective view of the valve and a portion of the valve casing.

In the embodiment disclosed, the drilling motor is generally designated by the reference numeral 5, and fluid operated feeding means is illustrated at 6. The two are engaged with an interposed head block 7 having formed on one side thereof a valve casing 8. The valve casing is provided with a tapered valve seat 9, from. which lead passageways l0 and 11 that direct motivefluid to the motor and feeding means. This structure is but diagrammatically outlined, and is well known to those skilled in the art.

Rotatably mounted in the casing is a tapered throttle valve 12 having an exposed actuating'handle 13 on its smaller end 'and provided with a longitudinal bore 14 open ing through its larger end. Lateral ports 1.5 and 16, communicating with the bore 14,

are adapted to move into and out of register with the passageways 10 and" 11, ac-

cordingly as the valve is rotated to open the base of the projection 17 constitutes one wall of this chamber, and a plug 21' is threaded into the outer end of the valve cas ing and carries a nipple 22 for coupling a hose line to the head block.

The outer wall of the valve casing'is provided with a relief port 23, which as shown in Figures 1 and 4, is in line with the body of the valve, but said body is provide with a recess 24 which opens into the chamber 19 and also registers with the port 23 when the valve is in closed position. When the valve is open, however, as shown inFigure 2, the recess 24 is out of line with the port 23, and said port is thus out OK from the chamber 19.

The action of the combination isas follows: When the valve is closed and fluid under pressure is in the valve casing, it will obviously act against the end of the'extension 17 and the closed end wall of the bore 14 to produce an end thrust. This fluid will also pass between the extension and the packing member 18 into the chamber 19, but there will beno pressure against the wall 20, since the relief port 23 is in communication with the chamber 19. The pressure against the end wall of the extension 17 and the bottom of the bore 14 is suflicient to hold the valve snugly seated, and yet it can be readily turned. If now it is turned to the position illustrated in Figure 2, the fluid pressure will pass into the drilling machine, but the relief port 23 is now out off from the chamber 19, so that pressure will build up therein and act against the face 20. In other words, an additional pressure surface becomes active to more tightly wedge the valve in its seat. However, this pressure is not as great as would be the case with the ordinary valve without the relief port and when such valve is closed, since the passage of the fluid through the drilling machine tends to. reduce the line pressure. The present valve therefore when in open position and having such reduced pressure against it. can consequently be turned to closed position and yet there is sufficient end thruston the valve by means of the fluid pressure to insure it at all times being held wherever placed.

From the foregoing, it is thought that the construction, operation and many advantages ofthe herein described invention will be apparent to those skilled in the art, without further description, and it will beflunderstood that various changes in the size, shape, proportion and minor details of construction, may be resorted to without departing from the spirit or sacrificing any of the advanta es of the invention.

Having thus ully described my invention, what I claim as new, and desire to secure by Letters Patent, is

1 In apparatus of the character set forth, the combination with a valve casing having a fluid inlet and a fluid outlet, of a rotary valve therein, means for creating end thrust on the valve, and means independent of said fluid outlet for varying the force of the thrust when the valve is shifted to different positions.

,2. In apparatus of the character set forth, the combination with a valve casing, of a valve therein rotatable between an open and a closed position, and means for creating an end thrust against the valve and automatically'increasing the power of the thrust when the valve is in open position.

3/In apparatus of the character set forth, the combination with a valve casing having a fluid inlet, a fluid outlet and a tapered seat, of a tapered valve rotatably mounted in the seat, means for creating end pressure against the larger end portion of the valve, and means independent of the fluid outlet for automatically varying the pressure when the valve is turned to a predetermined position.

4.' In apparatus of the character set forth, the combination with a valve casing having atapered seat, of a tapered valve rotatably mounted in the seat, and means for creating fluid pressure against the valve to a closed position, means for creating fluid pressure against the valve to produce end thrust, and means for automatically increasing the effective fluid pressure area when the valve is moved to open position.

6. In apparatus of the character set forth, the combination with a. valve casing, of a rotary valve j ournaled therein and movable between open and closed positions, means for creating fluid pressure endwise a ainst the valve, and means for automatical y relieving said fluid pressure when the valve is moved to its closed position.

7. In apparatus of the character set forth, the combination with a valve casing, of a rotary valve journaled therein and having a plurality of distinctive pressure receiving surfaces, means for permitting fluid under pressure to have access to said surfaces to create end thrust on the valve, and means for relieving the pressure against one of the surfaces when the valve is moved to a predetermined osition.

8. In apparatus of the character set forth, the combination with a valve casing, of a rotary valve journaled therein and having a plurality of distinctive pressure receiving surfaces,said valve being rotatable between open and closed positions, and means for permitting fluid under pressure to have access to said surfaces to create end thrust on the valve, said valve casing having a relief port that is opened to one of the pres sure surfaces when the valve is moved to closed position.

9. In apparatus of the character set forth, the combination with a valve casing havin a tapered valve seat, of a rotary tapered valve in the seat, means for delivering fluid under pressure to the larger end of the valve, means creating a chamber of which one of the end faces of the valve constitutes a wall, said valve casing having a relief port normally cut off from the chamber, and means establishing communication between the port and chamber when the Valve is in closed position.

In testimony whereof, I affix my signature in the presenceof two witnesses.

WILLIAM G. NAISMITH.

Witnesses SULLIVAN V. JOHNSON, JosErH SAMrsoN. 

